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We resolve the complexity of the point-boundary variant of the art gallery problem, showing that it is $\exists\mathbb{R}$-complete, meaning that it is equivalent under polynomial time reductions to deciding whether a system of polynomial…

Computational Geometry · Computer Science 2025-04-11 Jack Stade

This paper focuses on a variation of the Art Gallery problem that considers open edge guards and open mobile guards. A mobile guard can be placed on edges and diagonals of a polygon, and the "open" prefix means that the endpoints of such…

Computational Geometry · Computer Science 2013-06-20 Antonio Leslie Bajuelos , Santiago Canales , Gregorio Hernández , Mafalda Martins , Inês Matos

The Art Gallery Problem (AGP) is one of the classical problems in computational geometry. It asks for the minimum number of guards required to achieve visibility coverage of a given polygon. The AGP is well-known to be NP-hard even in…

The Art Gallery Problem (AGP) asks for placing a minimum number of stationary guards in a polygonal region P, such that all points in P are guarded. The problem is known to be NP-hard, and its inherent continuous structure (with both the…

Computational Geometry · Computer Science 2014-12-19 Sándor P. Fekete , Stephan Friedrichs , Alexander Kröller , Christiane Schmidt

In the problem "Localization and trilateration with the minimum number of landmarks", we faced the 3-Guard and classic Art Gallery Problems. The goal of the art gallery problem is to find the minimum number of guards within a simple polygon…

Computational Geometry · Computer Science 2025-03-14 Bahram Sadeghi Bigham , Sahar Badri , Nazanin Padkan

A polygonal art gallery can be observed by guards placed at one third of its corners. However, the strategy of placing guards at every third corner does not work for all art galleries. In this note, we provide an example of a nine-sided art…

Combinatorics · Mathematics 2019-08-06 Ralph Morrison

We study the Art Gallery Problem for face guards in polyhedral environments. The problem can be informally stated as: how many (not necessarily convex) windows should we place on the external walls of a dark building, in order to completely…

Computational Geometry · Computer Science 2014-04-22 Giovanni Viglietta

We will consider some extensions of the polygonal art gallery problem. In a recent paper Morrison has shown the smallest (9 sides) example of an art gallery that cannot be observed by guards placed in every third corner. Author also…

Computational Geometry · Computer Science 2019-09-20 Eryk Lipka

In the art gallery problem, we are given a closed polygon $P$, with rational coordinates and an integer $k$. We are asked whether it is possible to find a set (of guards) $G$ of size $k$ such that any point $p\in P$ is seen by a point in…

Computational Geometry · Computer Science 2026-03-18 Lucas Meijer , Tillmann Miltzow

We study the problem of guarding orthogonal art galleries with horizontal mobile guards (alternatively, vertical) and point guards, using "rectangular vision". We prove a sharp bound on the minimum number of point guards required to cover…

Combinatorics · Mathematics 2019-11-07 Ervin Győri , Tamás Róbert Mezei

There exist many variants of guarding an orthogonal polygon in an orthogonal fashion: sometimes a guard can see an entire rectangle, or along a staircase, or along an orthogonal path with at most $k$ bends. In this paper, we study all these…

Computational Geometry · Computer Science 2017-06-08 Therese Biedl , Saeed Mehrabi

Art Gallery is a fundamental visibility problem in Computational Geometry. The input consists of a simple polygon P, (possibly infinite) sets G and C of points within P, and an integer k; the task is to decide if at most k guards can be…

Computational Geometry · Computer Science 2020-03-18 Akanksha Agrawal , Kristine V. K. Knudsen , Daniel Lokshtanov , Saket Saurabh , Meirav Zehavi

We present two new versions of the chromatic art gallery problem that can improve upper bound of the required colors pretty well. In our version, we employ restricted angle guards so that these modern guards can visit $\alpha$-degree of…

Computational Geometry · Computer Science 2017-11-21 Hamid Hoorfar

We consider the problem of monitoring an art gallery modeled as a polygon, the edges of which are arcs of curves, with edge or mobile guards. Our focus is on piecewise-convex polygons, i.e., polygons that are locally convex, except possibly…

Computational Geometry · Computer Science 2011-03-01 Menelaos I. Karavelas

Art Gallery Localization (AGL) is the problem of placing a set $T$ of broadcast towers in a simple polygon $P$ in order for a point to locate itself in the interior. For any point $p \in P$: for each tower $t \in T \cap V(p)$ (where $V(p)$…

Computational Geometry · Computer Science 2018-11-30 Prosenjit Bose , Jean-Lou De Carufel , Alina Shaikhet , Michiel Smid

A sliding camera inside an orthogonal polygon $P$ is a point guard that travels back and forth along an orthogonal line segment $\gamma$ in $P$. The sliding camera $g$ can see a point $p$ in $P$ if the perpendicular from $p$ onto $\gamma$…

Computational Geometry · Computer Science 2016-04-26 Therese Biedl , Timothy M. Chan , Stephanie Lee , Saeed Mehrabi , Fabrizio Montecchiani , Hamideh Vosoughpour

We show the following problems are in $\textsf{P}$: 1. The contiguous art gallery problem -- a variation of the art gallery problem where each guard can protect a contiguous interval along the boundary of a simple polygon. This was posed at…

Computational Geometry · Computer Science 2025-06-24 Eliot W. Robson , Jack Spalding-Jamieson , Da Wei Zheng

This paper studies a variant of the Art Gallery problem in which the ``walls" can be replaced by \emph{reflecting edges}, which allows the guards to see further and thereby see a larger portion of the gallery. Given a simple polygon $\cal…

Computational Geometry · Computer Science 2023-04-06 Arash Vaezi , Bodhayan Roy , Mohammad Ghodsi

We study the Dispersive Art Gallery Problem with vertex guards: Given a polygon $\mathcal{P}$, with pairwise geodesic Euclidean vertex distance of at least $1$, and a rational number $\ell$; decide whether there is a set of vertex guards…

Computational Geometry · Computer Science 2024-06-11 Sándor P. Fekete , Joseph S. B. Mitchell , Christian Rieck , Christian Scheffer , Christiane Schmidt

We address recently proposed chromatic versions of the classic Art Gallery Problem. Assume a simple polygon $P$ is guarded by a finite set of point guards and each guard is assigned one of $t$ colors. Such a chromatic guarding is said to be…

Computational Geometry · Computer Science 2014-12-15 Frank Hoffmann , Klaus Kriegel , Max Willert